The taxonomic history of Prunus is long and complicated, in part due to the economic value of its fruit crops and also the ease with which some species hybridize. Here, Prunus is circumscribed in its broad sense based on the argument that when viewed on a worldwide scale, the morphologic discontinuities among the segregate genera diminish and they overlap with one another. Included here are species that have at times been placed in the genera Amygdalus, Armeniaca, Cerasus, Laurocerasus, Padus, and Persica.
At the species level, Prunus has been the object of the usual combining and splitting common among taxonomists with different philosophies and opinions. In particular, over-reliance on the indument of various vegetative and floral parts has led to the naming of numerous species and infraspecific taxa. Similarly, too much has been made of fruit colour and palatability in naming taxa of Prunus. It is very likely that, as molecular and genetic data are analyzed and, more importantly, correlated with morphological data, circumscriptions will be redrawn and the number of Prunus species will be reduced[].

Common Name: Chickasaw Plum

General Information

Prunus angustifolia is a spiny, deciduous shrub or small tree, usually growing 100 - 500cm tall. The plant often suckers and can form thickets[].
The plant is harvested from the wild for local use as a food and source of materials. It is sometimes cultivated for its edible fruit, especially in N. America, and is also grown as an ornamental[].
Prunus angustifolia is a widespread species with a stable population. Additionally, conservation measures are in place including in situ conservation in protected areas and ex situ conservation in Botanical Gardens and the NPGS. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The plant (especially the seed and young shoots) contains cyanogenic glycosides, especially amygdalin and prunasin. When injested, these compounds break down in the digestive tract to release cyanide. Used in small quantities in both traditional and conventional medicine, this exceedingly poisonous compound has been shown to stimulate respiration, improve digestion, and promote a sense of well-being[]. It is also claimed by some to be of benefit in the treatment of cancer - though this claim has been largely refuted.
In larger concentrations, however, cyanide can cause gasping, weakness, excitement, pupil dilation, spasms, convulsions, coma and respiratory failure leading to death[].
The fruits and flowers of most members of this genus generally have low or very low concentrations of this toxin, though the seeds and young shoots can contain much higher levels.
The levels of toxin can be detected by the level of bitterness:- for example sweet tasting almond seeds are a major food crop and are often eaten in quantity, whilst bitter tasting almond seeds are used as a flavouring (in marzipan for example) but are not usually eaten on their own.
In general, it can be considered safe to eat any fruit or seed from species in this genus that either have a sweet flavour or are slightly bitter. Great caution should be taken, however, if the flavour is moderately to very bitter[].

Botanical References

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Range

Southern and eastern N. America - Colorado to Pennsylvania and New Jersey, south to New Mexico, Texas and Florida

Habitat

Usually found in sandy soils, occurring along fence rows, in pastures, fields, open woods, stream banks, sand dunes and disturbed sites, often forming thickets; at elevations up to 600 metres[, ].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	3.00 m
Growth Rate	Medium
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Prunus angustifolia is winter-hardy to zone 6, but requires hot summers if it is going to thrive - in cool summer areas it generally does not do well and fruits poorly[]. One form of the plant, previously recognized as distinct (as Prunus watsonii Sarg.) generally grows better in regions of the temperate zone with cooler summers[].
Thrives in a well-drained moisture-retentive loamy soil[, ]. Succeeds in dry soils[]. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present[]. Succeeds in sun or partial shade though it fruits better in a sunny position[, ].
A fast-growing but short-lived tree in the wild[], it has become rather rare in a truly wild state[], though it is often cultivated for its edible fruit in N. America. There are some named varieties[, ]. The fruit is not freely produced in British gardens[].
Unlike the type species, the sub-species Prunus angustifolia watsonii (Sarg.) Waugh thrives in Britain[].
The flowers, which appear just before the leaves unfold, have a refreshing fruity scent[].
Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged[]. This species suckers freely in the wild, often forming thickets[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw, cooked or dried for later use[, , ]. Large and thin-skinned with a soft juicy sweet pulp, it has a delicious flavour and is very good eaten out of hand, whilst it can also be used in pies, preserves etc[, ]. The red to yellow, globose to ellipsoid fruit is 15 - 20mm in diameter[].

Seed - raw or cooked. Do not eat the seed if it is too bitter - see the notes above on toxicity.

Medicinal

Although no specific mention has been seen for this species, all members of the genus contain amygdalin and prunasin, substances which break down in water to form hydrocyanic acid (cyanide or prussic acid). In small amounts this exceedingly poisonous compound stimulates respiration, improves digestion and gives a sense of well-being[].

Agroforestry Uses:

This species is sometimes used in shelterbelt planting[, ]. It has an extensive root system and often forms thickets, which make it useful for erosion control[].

Other Uses

A green dye can be obtained from the leaves[].
A dark grey to green dye can be obtained from the fruit[].

This species is a secondary genetic relative of the Japanese Plum (Prunus salicina), and so it has the potential for use as a gene donor for crop improvement[].

Wood - heavy, rather soft, not strong[]. It weighs 43lb per cubic foot[] and is of little commercial value[].

Propagation

Seed - requires 2 - 3 months cold stratification and is best sown in a cold frame as soon as it is ripe[]. Sow stored seed in a cold frame as early in the year as possible[]. Protect the seed from mice etc. The seed can be rather slow, sometimes taking 18 months to germinate[]. Prick out the seedlings into individual pots when they are large enough to handle. Grow them on in a greenhouse or cold frame for their first winter and plant them out in late spring or early summer of the following year.
Cuttings of half-ripe wood with a heel, mid summer in a frame[, ].
Softwood cuttings from strongly growing plants in spring to early summer in a frame[].
Layering in spring.